U.S. Pat. No. 5,072,703 teaches apparatus for automatically starting and stopping a truck engine to conserve fuel while providing temperature control of a truck sleeper unit, and maintaining the engine in a ready-to-start condition. The apparatus of this patent works well in carrying out the required functions, but requires the expense of tailoring each such apparatus for the specific truck it is to be used with, and for accommodating the different needs and desires of different truck owners. For example, some truck engines are electronically controlled fuel injected engines, and some are not; and different truck engines have different numbers of teeth in the ring gear used for engine speed (RPM) detection, requiring each apparatus to be calibrated for the number of teeth in the ring gear of the truck it is to be used with. Some truck owners have different desires related to how an automatic engine control should operate relative to the position of the ignition switch, requiring the apparatus to be built in different models for different owners to accommodate the different options which are available. Some drivers do not like the engine starting and stopping during the sleeper unit temperature control mode, and will try to "fool" an engine start-stop system into operating all of the time, which thus defeats the fuel saving purpose of the apparatus. Further, the apparatus cannot detect and interpret different operating conditions and adapt to certain changing conditions in a way to more effectively carry out the purposes and functions of the apparatus.
Thus, it is an object of the present invention to provide new and improved methods for operating a truck engine in an automatic start-stop mode, when it is safe to do so, to conserve fuel while maintaining the truck engine in a ready-to-start condition, and while controlling the temperature of a truck sleeper unit when such temperature control is desired. The new methods should improve the flexibility of apparatus constructed according to the methods, accommodating different truck engine designs as well as different control options which may be desired by truck owners. The new methods should further sense when the system is being "fooled" into continuous operation, and should take appropriate action to maintain the desired start-stop fuel saving operation. Finally, the new methods and apparatus should sense when different operating conditions make the parameters being used inefficient, and should further be able to change or modify the parameters, at least until the operating conditions change back to where the parameters being used are effective.